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Metabolism and Nutrition Review Flashcards Preview

(5) 32-year-old male is on a weight maintenance diet, so he does not want to lose or gain any weight. Which amino acid must be present in the diet so the patient does not go into a negative nitrogen balance?alaninearginineglycinethreonineserine

GLYCINEThe lack of one essential amino acid will lead to a negative nitrogen balance due to increased protein degradation to supply that amino acid for the ongoing protein synthesis.

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(16) Consider a normal 25-year-old man, about 70 kg in weight, who has been shipwreckedon a desert island, with no food available, but plenty of freshwater. Which fuel stores is least likely to provide significant calories to the man?adipose triacylglycerolliver glycogenmuscle glycogenmuscle protein

(18) A vegan has been eating low-quality vegetable protein for many years, and is now exhibiting a negative nitrogen balance. This may be occurring due to a lack of which one of the following in his/her diet?linoleic acidstarchserinelysinelinolenic acid

LYSINELinoleic and linolenic acids are the essential fatty acids in the diet, and a lack of these fatty acids will not affect nitrogen balance. Starch is a glucose polymer, and the lack of starch will not affect nitrogen balance. Lysine is an essential amino acid, whereas serine can be synthesized from a derivative of glucose. Lack of lysine in the diet will lead to a neg- ative nitrogen balance as existing protein is degraded to provide lysine for new protein synthesis.

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(19) A medical student has been studying for exams, and neglects to eat anything for 12 hours. At this point, the student opens a large bag of pretzels and eats every one of them in a short period. What effects will this meal have on the student’s metabolic state?

Liver glycogen stores will be replenished.

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(20) After a stressful week of exams, a medical student sleeps for 15 hours, then rests in bed for an hour before getting up for the day. Under these conditions, which one of the following statements concerning the student’s metabolic state would be correct?A. liver glycogen stores are completely depletedB. liver gluconeogenesis has not yet been acticatedC. muscle glycogen stores are contributing to the maintenance of blood glucose levelsD. fatty acids are being released from adipose triacylglycerol stores

Fatty acids are being released from adipose triacylglycerol stores.

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(21) A physician working in a refugee camp in Africa notices a fair number of children with emaciated arms and legs, yet a large protruding stomach and abdomen. An analysis of the children’s blood would show significantly reduced levels of which one of the following as compared with those in a healthy child?glucoseketone bodiesalbuminfatty acidsglycogen

ALBUMINThe children are exhibiting the effects of kwashiorkor, a disorder resulting from adequate calorie intake but insufficient calories from protein. This results in the liver producing less serum albumin (due to the lack of essential amino acids), which affects the osmotic balance of the blood and the fluid in the interstitial spaces.

LOSS OF WEIGHTAll of these patients will lose weight

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An 18-year-old person with type 1 diabetes has not injected her insulin for 2 days. Her blood glucose is currently 600 mg/dL (normal values are 80 to 100 mg/dL). Which one of the following cells of her body can still utilize the blood glucose as an energy source?brain cellsmuscle cellsadipose cells

BRAIN CELLSMuscle and adipose cells require insulin to stimulate the transport of glucose into the cell, whereas the glucose transporters for the blood–brain barrier are always present,and are not responsive to insulin.

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A patient is brought to the emergency room after being found by search andrescue teams. He was mountain climbing,got caught in a sudden snowstorm, andhad to survive in a cave. He had no food for6 days. In adapting to these conditions, which metabolic process has increased rather than decreased?

The brain’s use of ketone bodies

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(33) A 27-year-old male got lost while hiking in Yosemite National Park. He was found 8 days later. He had nothing to eat and only water to drink before being rescued. What essential nutrient has he not received over the last 8 days?lactic acidoleic acidsteric acidEPApalmitic acid

EPAEicosapentaenoic acid (EPA, a 20-carbon fatty acid containing five double bonds) can be derived from an essential fatty acid found in fish oils (linolenic acid), and isa precursor of eicosanoids (prostaglandins, leukotrienes, and thromboxanes).